Dendrimers are highly branched macromolecules formed by successive reactions of polyfunctional monomers around a core. Accordingly, as dendrimers grow from their core, their number of branches and terminal end groups increase, thereby increasing the density of these molecules at their peripheral surface.
Dendrimers are distinguishable from polymers because they are non-linear, hyper-branched structures that are synthesized in iterative fashion. The monomers from which they are constructed can generally be defined as AB.sub.n monomers, where n is usually 2 or 3, rather than the standard AB monomers, which produce linear polymers. Accordingly, each iteration of step-wise synthetic growth generally requires twice the number of monomers used in the previous iteration in the case of an AB.sub.2 monomer, or three times the number of monomers in the case of an AB.sub.3 monomer. The layer of monomers added in each iteration is called a generation. The ultimate generation, or that generation farthest from the core, produces the periphery of the molecule.
Because dendrimers are produced in iterative fashion, they can be synthesized to very high molecular weight molecules with narrow molecular weight distributions. Moreover, the nature of each generation can be controlled by controlling the type of monomer employed including the periphery or end groups.
Based on the foregoing, and the relative novelty of dendritic structures, the present invention furthers the art by making advancements in the modification of dendrimer structures, especially in their ability to act as, or produce, a shell to entrap smaller molecules.